CN111504405B

CN111504405B - A pipeline flow measurement device and method based on convective heat transfer phenomenon

Info

Publication number: CN111504405B
Application number: CN202010348448.8A
Authority: CN
Inventors: 郭航; 王海渝; 徐俊增; 廖林仙; 顾哲; 李帅
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2021-08-31
Anticipated expiration: 2040-04-28
Also published as: CN111504405A

Abstract

The invention discloses a pipeline flow measurement device and method based on convective heat transfer phenomenon. The measurement device is composed of a pipeline, a heat insulation layer, a heater, a temperature sensor and a data acquisition and analysis system. A partition is installed inside the pipeline of the device. The thermal layer uses a heater outside the pipeline to rapidly heat the pipeline locally; the temperature sensor is installed in the heated area of the pipeline and is connected to the single chip microcomputer for control; the single chip microcomputer obtains the liquid flow through the pipeline by analyzing the data sent by the temperature sensor. . The measuring device provided by the invention is easy to operate, and the measurement data obtained by converting the flow measurement into the instant temperature measurement method of the heated pipeline is reliable, and the accuracy of the flow measurement is also improved, and is widely used in many fields such as industry, agriculture, environment, etc. Pipeline flow measurement.

Description

Pipeline flow measuring device and method based on convective heat transfer phenomenon

Technical Field

The invention belongs to the measurement of pipeline flow, and particularly relates to a pipeline flow measuring device and method based on a convective heat transfer phenomenon.

Background

With the rapid development of industrial technology, the flow measurement technology is mature day by day and is widely applied to the fields of farmland irrigation, water conservancy engineering, petrochemical industry, metallurgy, pharmacy and the like. At present, the liquid flowmeter is commonly provided with a positive displacement flowmeter, a differential pressure flowmeter, a float flowmeter, a turbine flowmeter, an electromagnetic flowmeter and the like. However, when the liquid flowmeter of the pipeline is used in various industries, the problem that offline inspection cannot be carried out due to inconvenient disassembly is generally existed, so that a flow measuring means with accurate measuring result, convenient assembly and disassembly and economic price is urgently needed.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems of complex structure and low precision of the existing pipeline liquid flowmeter, the invention aims to provide a pipeline flow measuring device based on the convective heat transfer phenomenon, which is convenient to use; the second purpose of the invention is to provide a method for measuring the pipeline flow based on the convective heat transfer phenomenon.

The technical scheme is as follows: a pipeline flow measuring device based on a convective heat transfer phenomenon comprises a pipeline, a heat insulation layer, a heater, a temperature sensor and a single chip microcomputer, wherein the heat insulation layer is arranged in a heated area of the pipeline, and the heater is arranged at the bottom of the heated area of the pipeline to locally and rapidly heat the pipeline; the temperature sensor is arranged in a heated area of the pipeline and connected with the singlechip, and the singlechip analyzes the temperature change information of the pipeline sent by the temperature sensor to realize the measurement of the flow of the pipeline.

The insulating layer in the pipeline flow measuring device divides the liquid flowing through the pipeline into two parts, wherein one part of the liquid flows through the insulating thin-wall round pipe; another portion of the liquid flows through the conduit for carrying away heat from the heated conduit.

Furthermore, the heat insulation layer is composed of a heat insulation thin-wall round pipe and a heat insulation support. The heat-insulation thin-wall circular tube is arranged in the heated area of the pipeline and supported by the heat-insulation support, so that the heat-insulation thin-wall circular tube is fixed at the central position in the pipeline, and water flow passing through the outer side of the heat-insulation layer is uniformly distributed when water flow in the pipeline passes through the heat-insulation layer.

Furthermore, the temperature sensors are three thermocouple K-type sheet temperature sensors which are respectively stuck to the heated area of the pipeline and the upstream and downstream pipelines of the area, so that the accurate measurement of the temperature change of the pipeline is ensured, and the temperature change is fed back to the singlechip for flow measurement.

Furthermore, the temperature sensor also comprises a non-contact infrared dot matrix temperature measuring module, the non-contact infrared dot matrix temperature measuring module is installed on one side of the heated area of the pipeline, the temperature vertical distribution of the heated area of the pipeline is monitored, and the function of checking whether liquid in the pipeline is in a full flow state or a non-full flow state is achieved.

Based on the pipeline flow measuring device, the invention also provides a pipeline flow measuring method based on the convective heat transfer phenomenon, which comprises the following steps:

(S1) before detection, firstly, aiming at the heat conduction property of the liquid in the measured pipeline, selecting the proper highest temperature T for heating the pipeline by a heater, and ensuring that the time for the liquid flowing through the pipeline to take away heat meets the requirement of the measurement process; then, a heater is used for locally heating the pipeline provided with the heat insulation layer to a temperature T, different flow rates of liquid flowing through the pipeline are simulated, a temperature sensor collects pipeline temperature change information under different flow rates and transmits the pipeline temperature change information to a single chip microcomputer, and the single chip microcomputer establishes a database with a temperature change rate corresponding to the liquid flow rate;

(S2) during detection, firstly closing a pipeline valve to enable no liquid to pass through the pipeline, locally heating the pipeline provided with the heat insulation layer to a temperature T by using a heater, then opening the valve to enable the liquid to flow through the pipeline to take away heat, acquiring the temperature change condition of the pipeline under the actual flow rate by using a temperature sensor, transmitting the temperature change condition to a single chip microcomputer, comparing the temperature change condition with a database by using the single chip microcomputer, and obtaining the pipeline liquid flow rate corresponding to the temperature change information.

Further, in the step (S1) and the step (S2), the temperature sensor is a thermocouple K-type sheet temperature sensor, the thermocouple K-type sheet temperature sensor transmits temperature information of a heated area of the pipeline and upstream and downstream pipeline positions of the heated area to the single chip microcomputer, and the single chip microcomputer can judge whether temperature values at three points are equal according to a built-in program, so that a temperature constant point of the whole pipeline is determined.

Further, in the step (S1) and the step (S2), after the single chip determines the constant point of the overall temperature of the pipeline, the single chip may determine the flow rate of the liquid flowing through the pipeline according to the speed of the temperature T of the pipeline after being heated to be reduced to the constant temperature rate when the liquid flows through the pipeline.

Drawings

FIG. 1 is a schematic view of the configuration of a pipe flow measuring device according to the present invention;

fig. 2 is a schematic structural view of a pipe flow rate measuring device described in the embodiment.

Detailed Description

In order to explain the technical scheme disclosed by the invention in detail, the invention is further described in detail by combining the attached drawings of the specification.

As shown in fig. 1-2, the device for measuring the flow of a pipeline based on the convective heat transfer phenomenon mainly comprises a pipeline 101, a heat insulation layer 102, a heater 103, a temperature sensor 104, a single chip microcomputer 105, a heat insulation support 201, a heat insulation thin-wall circular tube 202, a thermocouple K-type thin-sheet temperature measurement sensor 401 and a non-contact infrared dot matrix temperature measurement module 402.

The single chip microcomputer 105 of this embodiment establishes a database of temperature information corresponding to the simulated flow rate of the pipeline according to the temperature information of the pipeline 101 at the simulated flow rate, which is acquired by the temperature sensor 104, and obtains the flow rate of the pipeline liquid by calling the database to analyze the temperature change information to be diagnosed, which is acquired by the temperature sensor 104. In the embodiment, a heat insulation layer is arranged in a heated area of the pipeline 101, a heater 103 is arranged at the bottom of the pipeline, and the pipeline 101 is locally and rapidly heated; the heat insulation layer 102 is composed of a heat insulation thin-wall round pipe 202 and a heat insulation support 201, the heat insulation thin-wall round pipe 202 is arranged in the heated area of the pipeline 101 and is supported by the heat insulation support 201, so that the heat insulation thin-wall round pipe 202 is fixed at the central position in the pipeline 101, and water flow passing through the outer side of the heat insulation layer 102 is uniformly distributed when water in the pipeline passes through the heat insulation layer.

The temperature sensor 104 in this embodiment is composed of three thermocouple K-type sheet temperature sensors 401 and a non-contact infrared dot matrix temperature measurement module 402, and is connected to the single chip microcomputer 105, so that the single chip microcomputer 105 can determine the flow rate of liquid in the pipeline after receiving temperature change information measured by the thermocouple K-type sheet temperature sensors 401 at the heated area of the pipeline and the upstream and downstream pipelines of the area; after receiving the vertical distribution information of the temperature of the side surface of the heated area of the pipeline transmitted by the non-contact infrared dot matrix temperature measurement module 402, the function of checking whether the liquid in the pipeline is in a full flow state or a non-full flow state is realized.

Whole device need mark on the spot before using, and the suitable highest temperature that the pipeline was heated is set up according to the interior liquid physical property of pipeline that awaits measuring earlier to the calibration process needs, guarantees that the liquid flow takes away thermal time through the pipeline and satisfies the measurement process needs, avoids because liquid specific heat capacity is great, and heating temperature is lower, causes the inaccuracy of pipeline flow measurement result. And then, a corresponding reference database is formulated by utilizing the singlechip according to temperature change information, which is transmitted by the temperature sensor and is generated when the liquid in the pipeline has different flow rates, so that the flow rate to be measured of the liquid in the pipeline corresponds to the temperature change information one by one.

The pipeline flow measuring method implemented based on the pipeline flow measuring device comprises the following specific steps:

(S1) before use, firstly, aiming at the heat conduction property of the liquid in the measured pipeline 101, selecting the proper highest temperature T for heating the pipeline by the heater 103, and ensuring that the time for the liquid to flow through the pipeline to take away heat meets the requirement of the measurement process;

(S2) locally heating the pipe with the thermal insulation layer 102 to a temperature T by using a heater, simulating different flow rates of liquid flowing through the pipe, and providing a set of reliable reference information of pipe temperature change for the single chip microcomputer 105 by using corresponding temperature change information transmitted by the thermocouple K-type sheet temperature sensor 401: closing a pipeline valve, opening a heater 103 to heat the area of the pipeline containing the heat insulation layer 102 to a proper maximum temperature T, closing the heater 103, opening the valve, taking away heat of liquid through the heated area of the pipeline to cool the pipeline, adjusting the size of the valve, repeating the steps, and enabling a thermocouple K-type sheet temperature measurement sensor 401 to record temperature change conditions corresponding to different flow rates and transmit the temperature change conditions to a single chip microcomputer 105 to serve as temperature change reference information;

(S3) when in use, comparing the temperature change information of the pipeline with the reference information by using the singlechip 105 to obtain a flow value in the pipeline; when the temperature measuring device is used, the liquid full flow or non-full flow state in the pipeline can be checked by utilizing the vertical distribution information of the temperature of the side surface of the heated area of the pipeline, which is received by the singlechip 105 and transmitted by the non-contact infrared dot matrix temperature measuring module 402.

Claims

1. A pipeline flow measurement device based on convective heat transfer phenomenon, characterized in that: it comprises pipeline (101), thermal insulation layer (102), heater (103), temperature sensor (104) and single-chip microcomputer (105), The heated area of the pipeline (101) has a built-in thermal insulation layer (102), and a heater (103) is installed at the bottom to rapidly heat the pipeline (101) locally; the temperature sensor (104) is installed on the heated area of the pipeline (101). The heating area is connected to the single-chip microcomputer (105), and the single-chip microcomputer (105) processes the pipeline temperature change information sent by the temperature sensor (104) to realize the pipeline flow measurement; (202) and a heat insulating support (201); the heat insulating thin-walled round pipe (202) is built in the heated area of the pipe (101), supported by the heat insulating support (201), and fixed at the inner central position of the pipe (101), When the water flow in the pipeline passes, the water flow passing through the outer side of the thermal insulation layer (102) is evenly distributed.

2. The pipeline flow measurement device based on convective heat transfer phenomenon according to claim 1, characterized in that: the temperature sensor (104) comprises three thermocouple K-type sheet temperature measurement sensors (401), and the thermocouple The K-type sheet temperature sensor (401) is respectively attached to the heated area of the pipeline (101) and the upstream and downstream pipelines of the area, and is used to detect the temperature change of the pipeline and feed back the measurement data to the microcontroller (105) for flow measurement.

3. The pipeline flow measurement device based on the convective heat transfer phenomenon according to claim 2, wherein the temperature sensor (104) further comprises a non-contact infrared lattice temperature measurement module (402), the non-contact infrared The lattice temperature measuring module (402) is installed on one side of the heated area of the pipeline (101), monitors the vertical temperature distribution of the heated area of the pipeline, and realizes the function of checking whether the liquid in the pipeline is in a state of full flow or non-full flow.

4 . The pipeline flow measurement device based on convective heat transfer phenomenon according to claim 1 , wherein the thermal insulation layer in the pipeline flow measurement device divides the liquid flowing through the pipeline into two parts, wherein a part of the liquid flows through the pipeline. 5 . Adiabatic thin-walled round pipe (202); another part of the liquid flows through the pipe (101) to take away the heat of the heated pipe.

5. A kind of pipeline flow measuring method based on convective heat transfer phenomenon of the pipeline flow measuring device as claimed in claim 1, is characterized in that: comprising the following steps:

(S1) Before the detection, first, according to the thermal conductivity of the liquid in the measured pipeline, select a suitable maximum temperature T for heating the pipeline (101) by the heater (103), so that the time for the liquid to take away heat through the pipeline satisfies the measurement process Required; then use the heater (103) to locally heat the pipeline with the thermal insulation layer (102) installed to the temperature T, and simulate different flow rates of the liquid flowing through the pipeline, and the temperature sensor (104) collects the pipeline temperature under different flow rates. The change information is transmitted to the single-chip microcomputer (105), and the single-chip computer (105) establishes a database corresponding to the temperature change rate and the liquid flow rate;

(S2) When testing, firstly close the pipeline valve so that no liquid can pass through the pipeline, use a heater (103) to locally heat the pipeline (101) where the thermal insulation layer (102) is installed to a temperature T, and then open the valve to allow the liquid to flow through The pipe takes away the heat, and the temperature sensor (104) collects the temperature change of the pipe under the actual flow rate, and transmits it to the single-chip microcomputer (105), and the single-chip computer (105) compares the temperature change information with the database, and obtains the corresponding temperature change information. pipe liquid flow.

6. The pipeline flow measurement method based on convective heat transfer phenomenon according to claim 5, characterized in that: in the method, the temperature sensor is a thermocouple K-type wafer temperature sensor, and the thermocouple K-type wafer temperature sensor The temperature information of the heated area and the upstream and downstream pipelines of this area is transmitted to the single-chip microcomputer, and the single-chip computer determines whether the temperature values of the three points are equal to determine the constant point of the overall temperature of the pipeline.

7. The pipeline flow measurement method based on convective heat transfer phenomenon according to claim 6, characterized in that: in the method, after the single-chip microcomputer determines the constant point of the overall temperature of the pipeline, when the liquid flows through, the pipeline decreases from the heated temperature T. The speed to a constant temperature rate determines the flow rate of the liquid flowing through the pipe.